Question

Which of the following formulas represents the same geometric sequence as the formula below

Answer 1

It has to be a or b since putting a 1 in for n gives

`2*5^(^1^-^1^)=2*5^0=2*1=2`
If you put n-1 in for n you get

`a_(n-1)=2*5^((n-1-1))=2*5^((n-2))`
Now for any a_n we need the total sequence before it as well as the nth value. But the total sequence before it is just a_(n-1):

`2*5^((n-2))*5=2*5^((n-1))`
so we need choice a, since the (n-1)th term times 5 is the nth term

Answer 2

The answer would have to be c.